US mogul Steve Wynn has resigned from his casino company Wynn Resorts, as the billionaire battles claims that he routinely subjected women who worked for him to unwanted sexual advances.

Wynn has denied the accusations published by the Wall Street Journal as "preposterous" and said they were instigated by his ex-wife to seek advantage in their divorce lawsuit.

He resigned as the finance chairman of the US Republican Party's fundraising arm, the Republican National Committee, in January.

"In the last couple of weeks, I have found myself the focus of an avalanche of negative publicity...I have reached the conclusion I cannot continue to be effective in my current roles," Wynn said in a statement.

The company said it has appointed Matt Maddox, its president since 2013, as CEO and Boone Wayson as non-executive chairman effective immediately.

Maddox has also been a non-executive director of Wynn Macau Ltd , a majority owned subsidiary of the Las Vegas-based company. Until 2014, Maddox was also its chief financial officer, according to the company website.